Will everyone exposed to common dusts get hypersensitivity pneumonitis?

No, only a small number of people exposed to common workplace dusts get hypersensitivity pneumonitis. Development of this disease typically takes prolonged or intense exposure to the allergen. Sometimes it is the combination of the allergic reaction and the response of the body's immune system that makes lung damage occur. The way the body's immune system reacts to the allergy may be what leads to inflammation.